Application Scenarios:

In a 600MW thermal power plant’s turbine governor system, the ABB SPHSS13​ module is deployed to control the main steam stop valves. The module receives a speed/load reference signal from the main controller (e.g., HPC80/HR series) via the Harmony Rack backplane. It then drives the electro-hydraulic servo valve to adjust the actuator position. The dual LVDTs provide redundant position feedback to the module, which runs a PI control algorithm to eliminate error. During a routine maintenance window, a technician can perform a hot-swap replacement​ of the SPHSS13 module without shutting down the entire DCS rack, thanks to its online insertion/removal capability, ensuring near-zero control system downtime.

 

Parameter:

Parameter Category	Specification Details
Product Model​	ABB SPHSS13​
Product Type​	Hydraulic Servo Control Module
Compatible Systems​	ABB Symphony Plus, Harmony Rack, Bailey INFI 90
Control Modes​	PI (Proportional-Integral), P-Only (Proportional Only)
Servo Output​	±300 mA (Servo Valve), 4-20 mA / 20-160 mA (I/H Converter)
Redundancy​	Dual Redundant Servo Coils, Dual LVDT Feedback Inputs
LVDT Support​	AC or DC LVDTs (Linear Variable Differential Transformer)
Digital I/O​	3 Isolated Digital Inputs (Raise/Lower/Trip), 1 Digital Output
Power Supply​	+5V, ±15V (from rack), +24V DC (from termination unit)
Operating Temp.​	0°C to +70°C (industrial standard)
Dimensions (HxWxD)​	~177.8 mm x 35.56 mm x 298.45 mm (Standard Harmony Card)
Hot-Swap​	Supported (with proper system procedure)

 

 

Technical Principles and Innovative Values:

• Innovation Point 1: Dual-Channel Redundancy for Critical Availability:​ Unlike standard servo drivers, the SPHSS13​ implements a fully redundant architecture. It features two independent servo coil outputs​ and supports dual LVDT position feedback​ sensors. If the primary coil or LVDT fails, the module can automatically or manually switch to the secondary channel without interrupting the control loop. This “single-fault tolerant” design is crucial for turbine control systems where unexpected downtime can cost millions per hour.
• Innovation Point 2: Integrated PI Control Algorithm:​ The module is not just a simple signal converter; it contains an onboard microprocessor that executes PI (Proportional-Integral) control algorithms​ locally. This allows it to function as a smart servo controller, calculating the precise output current needed to minimize the position error between the setpoint and the LVDT feedback, providing fast and stable response to governor commands.
• Innovation Point 3: Backward Compatibility and Hot-Swap Capability:​ The SPHSS13​ is designed as a direct successor to older modules like the IMHSS03​ and IMHSS13. It maintains mechanical and electrical compatibility with existing Harmony Rack systems, allowing for straightforward upgrades of legacy Bailey INFI 90 installations without rewiring the entire cabinet. Its support for online hot-swap​ (when enabled by the system configuration) allows for maintenance and replacement without a full unit shutdown, a critical feature for continuous process industries.

 

Application Cases and Industry Value:

Case Study: Gas Turbine Fuel Valve Control RetrofitA combined-cycle gas turbine (CCGT) plant was experiencing erratic fuel valve control due to aging servo modules in its legacy Bailey INFI 90 system. The plant engineers replaced the old IMHSS03 modules with ABB SPHSS13​ units. The new modules’ support for dual LVDT feedback allowed the plant to utilize existing sensor wiring while adding a second LVDT for redundancy. The improved PI control logic and higher drive current capability (±300mA) resulted in smoother valve modulation and a 15% reduction in fuel valve hunting during load ramps. The project extended the life of the existing DCS by 15+ years at a fraction of the cost of a full system replacement.